What is the ruling on saying to one's wife, after she has provoked him, "I divorce you that you don't understand"?

As long as you swore truthfully according to your belief, your oath does not result in divorce, and nothing is binding upon you, even if the reality of the matter was contrary to what you swore upon. The correct view is that whoever swears upon something he believes to be true, and it turns out to be otherwise, no divorce occurs. Swearing by divorce is forbidden by Islamic law and is considered an oath of the wicked. Some scholars have deemed it prohibited, while others consider it disliked.